Initially scans were obtained throughout the neck without IV contrast. Following this, a bolus of IV contrast was given and rapid scans obtained through the region of interest in the neck, related to the left lobe of the thyroid. As demonstrated on the recent ultrasound, there is a well-defined oblong mass in the left neck measuring $2.2 \times 3 \times 1.8cm$ in size. This lies posterolateral to the left thyroid lobe and is predominantly between the left common carotid artery, which is displaced posteromedially, and the left internal jugular vein, which is displaced laterally. No other adenopathy, and the remainder of the thyroid appears unremarkable.
IMPRESSION: The mass appears to be extrinsic to the thyroid, possible even within the carotid sheath. The lesion appears to be relatively avascular. The differential diagnosis would include an unusually enlarged lymph node, a very atypical thyroid nodule, or a soft tissue tumor. The lesion is very easily accessible to needle biopsy and this would certainly be the easiest method of obtaining positive confirmation. This could be done using US guidance.
1. What type of radiologic test is described here?
A. Ultrasound
B. CT scans
C. Pyelogram
D. PET scan
2. Where is the mass located?
A. Within the left lobe of the thyroid gland
B. Between the left and right carotid arteries
C. Behind and to the side of the left lobe of the thyroid gland
D. In front and to the side of the thyroid gland
3. Which of the following is not a possible diagnosis?
A. An unusual mass on the thyroid gland
B. Lymphadenopathy
C. Tumor mass adjacent to the thyroid gland
D. Lesion composed of many blood vessels
4. What procedure will help determine the diagnosis?
A. Aspiration of tissue and pathologic examination
B. Removal of the thyroid gland
C. Removal of thyroid tissue for biopsy
D. Further scans with ultrasound guidance
